


Steady Does It

by orphan_account



Category: Undertale (Video Game)
Genre: Anal Plug, Aphrodisiacs, Begging, Come Inflation, Gen, Knotting, Mating Cycles/In Heat, Monster Heat, Multiple Orgasms, Overstimulation, Plot What Plot/Porn Without Plot, Praise Kink, Reader Insert, Skeleton Penis, reader has a dick fyi, sharp teeth, skeleton fuckery, skeleton vag, this is just really kinky
Language: English
Status: Completed
Published: 2015-12-07
Updated: 2015-12-07
Packaged: 2018-05-05 10:18:44
Rating: Not Rated
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 3,763
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/5371682
Author URL: https://archiveofourown.org/users/orphan_account/pseuds/orphan_account
Summary: <blockquote class="userstuff">
              <p>Papyrus goes into heat.  Monster heat, to be exact.  I also noticed that most reader inserts cater to people with vaginas (which is nice, bc I have a vag, but I feel for the peeps with a schlong).  You fuck the skeleton and he fucks you a couple times.  lmao.</p>
            </blockquote>





	Steady Does It

**Author's Note:**

> The first time I write smut and it's fucking skeleton sin, and the kinkiest trash to the right of Las Vegas. Pray for my sins, you guys, cause I'm buring in skeleton fucking hell.

You're sitting in the kitchen when you get a text from Sans.

 

> **Pun-skull:  hey kid im headin out tonight.**
> 
> **Pun-skull:  come take care of pap for me while im out**
> 
> **You:  This isn't a trap, right?  You aren't going to just pretend to leave and then interrupt me and my skeleton smooching with incidental music or pranks?**
> 
> **You:  Bc I will be so dissapointed in you.**
> 
> **Pun-skull:  nah**
> 
> **Pun-skull:  thats just rude.  you kids have fun**
> 
>  

And that is how you ended up at the house of the brothers, entering without knocking.  You feel cheerful considering your boyfriend is in the kitchen clattering about.  You sneak up behind him, as he hums happily to a tune you hear often.  You wrap your arms around him, nuzzling his back sweetly.  "Hey, Boo," you whisper, as he jumps slightly.

 

"(F-F/N)!  YOU SHOULD NOT SNEAK UP LIKE THAT!  I DIDN'T HEAR YOU COME IN!  ARE YOU JOINING ME FOR DINNER WHILE SANS IS AWAY DOING... WHATEVER IT IS SANS IS DOING...?" he says, stumbling over words in his surprise.

 

You giggle, fingers tapping his hips.  "Yup, just the two of us tonight," you leave the implication hanging, knowing he probably won't get it.

 

Like predicted, he doesn't, and moves on.  "THAT'S WONDERFUL!  I WAS HOPING TO HAVE COMPANY TONIGHT, I'VE BEEN A BIT 'BONLEY' THESE PAST FEW DAYS FOR SOME REASON... NYEH-HEH-HEH-HEH-HEH!" he says laughing at his own joke.  So adorable.  If he wasn't so lovable you wouldn't put up with his doofy jokes.

 

You get on your tip toes and nip the back of the cervical vertabrae of his neck.  To your surprise, he jumps slightly, and his hips stutter to yours, before he rapidly jumps away before you can do anything.  He has his back to the counter, and a hand over his mouth, orange blush burning bright.  You'd laugh if you weren't so concerned.  "Pap?  Baby, are you okay?"

 

"I-I... I DON'T-" he stutters, not seeming to be able to get anything out.

 

You sternly look at him, and he wriggles on the spot, pressing his hips away from you.  "Pap.  If I hurt you, you gotta let me know, so I don't do it again," he's shivering as you speak, and makes an almost inaudible whimper.  It would be really fucking hot if you weren't so worried.  "Use your words, babe".

 

"I-I'M SORRY.  YOU DIDN'T HURT ME," he says softly, still trembling.  You touch his hand with yours, slowly advancing, not wanting to scare him.

 

"Then why did you- what's that smell?" you frown in confusion, as another smell breaks through the smell of burning spaghetti; it's thick, musky, and smells vaguely like...  _oh._   "Pap?  What's going on?"  You think you know the answer.

 

"I- AH... BELIEVE I MAY BE... OH, THIS IS SO EMBARRASSING, I BELIEVE I MAY BE GOING INTO HEAT..." he says shyly, shuffling his feet, unconsciously leaning tword you.  He shuts off the burners.  "WE MAY HAVE TO CUT THE EVENING SHORT.  I UNDERSTAND IF YOU WANT TO LEAVE".

 

"What?  No way, Papyrus, I want to help!  If I can help you through this, I will!"

 

He looks up sharply, color bursting on his cheeks.  "I FEAR I NEED A DIFFERENT KIND OF HELP, (F/N).  THE-AH-SEXUAL KIND.  I WOULD NEVER FORCE YOU INTO SOMETHING SO SUDDEN AND INTIMATE".

 

You smile softly, and put your hand on his cheek.  He nuzzles it softly, quietly... purring?  Yeah, that's what it sounds like.  "Babe, I've been... wanting to be intimate with you for a while... I just didn't know how to propose that sort of stuff to you.  You never really showed any interest in it, I mean".

 

He perks.  "W-WELL.  I GUESS WE HAVE BOTH BEEN A COUPLE OF 'NUMBSKULLS'... HAVEN'T WE...?"

 

This boy is lucky you love him, or his soul wouldn't be the only blue thing of his.

 

With a little more coercion from you, he shyly pulls you to his room, fondly rubbing your knuckles with his thumb.  At one point, the heat hits him hard, and an orange puddle forms on his shorts, and drips onto his legs as he stumbles.  You pick him up gracelessly and rush to his room, because fuck, that smell is driving you crazy by now.  You set him on the bed, a little roughly, you're ashamed to admit, but Papyrus doesn't seem to care much, falling backwards into his race car bed. 

 

You slowly crawl up to him, giving him enough time to say no, or push you away.  He does the exact opposite in fact, pulling you up and pressing his hips to yours.   You expect to feel nothing but bones, but to your surprise, you feel a thick... something in his shorts.  Another gush of the slick something comes through his soaking shorts.  He arches and whimpers under your hands, which have found his ribs, and have knotted your fingers between them.  "Ya like that, babe?  Look so pretty, all spread out for me," you pant.  You'd always been a little more vocal in bed.  There were people that hated it, and people that couldn't get enough of it.  It was pretty easy to see which one you boyfriend was going to be.

 

He writhes under you, grinding your hips together, crying out softly.  "O-OH GOSH I- P-PLE-ASE!"

 

You slowly unhook your hands from his ribs, pressing down on his vertebrae until you reach his hips.  You kiss the hip of his pelvis just enough to make him squirm, eagerly pulling down his shorts and underwear in a single pull, curious of what your boyfriend is packing.  You are not dissapointed.

 

He's got a sort of gelatinous looking pair of organ-like structures, both of which are pulsing phantasmic orange glow.  The... well you can't really call it a dick; It's long and thick, and has pearl-like bumps along the shaft of it to the base, where there's a thickening in it that looks like some sort of knot.  There's a thick ridging near the head, and a small slit at the tip, where pale, glowing streams of come are pearling on the tip.  Below it, is what is possibly a vagina, but not quite.  It's a soft looking pucker, with a small bud beyond a pair of lips that have already spred that's wildly flexing, and squirts a small amount of slick onto the sheets.

 

You lean in, and breathe deeply.  He smells so good, you feel yourself actually begin to salivate.  The drool slips before you can catch it and slides onto the head of Papyrus's cock.  He jumps slightly, and looks down at you impatiently panting.  "PLEASE, (F/N), YOU PROMISED TO HELP-AH!" he cries, pleading as he humps tword your face encouragingly, trying to get his message across.

 

You decide you've tortured him enough.  You lean forward, crossing an arm across his hips firmly, before using your fingers to part the lips of his pucker, as you decide it's as good a place to start as any.  You really want to get in him anyway.  He juices a little onto your face, and before he can apologize, you lick his slit gently.  Like predicted, he heaves under you, hips trying to ride your mouth, your arm preventing him.  His vibrant whine is the only warning you get, before a larger gush of slick pours onto your tongue.  He tastes thick and deep, and vaguely slow.  You drink him in sweetly with another lick, tongue eager for more of him, your tongue pushing past the ring of muscle.  It's not as warm as a human, but it's  _very_  wet and so soft and silky.  He's arching and mewling beneath your ministrations, and you've barley started yet.

 

Slurping softly, you use a hand to slip a finger in, and he trembles, breaths coming in heavy gasps.  You almost grin in delight.  The insides of the puckered slit are  _ridged_.  He's going to be so good for you.  He's already so achingly wet as you slip another into the tight passage and curl them, looking to his face for a reaction.  He sobs in ecstasy clenching tightly around your fingers, eyes closed and mouth wide.  "You're so good for me, baby boy.  Can't wait to get in you for real, gonna make you come so hard".  Your only response is a gasp and an arch, as he rides your fingers.  You stop him, pressing your arm onto his hips more firmly.  "Come on, babe.  You want me to eat you out or not?"

 

He babbles rapidly, trying to get something out, but you move to the slit anyway, his cock dripping into your hair.  You lick the slit again, before curiously flattening your tongue to the bud above the pucker, wondering if it works like a clit.  You are pleasantly answered with a gush of slick as you slip another two fingers into him with surprising ease, and a howl from Papyrus.  You smile and contract your lips to a kiss, and suck harshly on the large bud.  He cries loudly, hands flying to your head that were previously grinding the sheets, pressing your smooth muscle into the bud.  You work your fingers harder, as you swirl your tongue around his pearl, before moving your thumb to press him between your finger and the bud.  He screams as he comes suddenly in pleasure, the cock bobbing and twitching above you, working at the air.  The sudden pouring of liquid into your mouth leaves you breathless, almost literally, as you drink from the slit, lapping at his entrance.  His hands in your hair are rubbing your scalp harshly as he comes down slowly.

 

You pull up and he murmurs his unhappiness with the loss, his hands trying to tug you back to the slit.  You feel so... immersed.  His slick must be made of magic, because it's working you like crazy, your eyes noticing things rapidly, mind working quickly, and your own shaft hardening rapidly.  "Think you're ready, baby doll?  Wanna feel me?" you pant, pulling your shirt and pants off, leaving you in your boxers, pressing your bulge to the soft wetness between his thighs.

 

He sobs softly.  "P-PLEASE, (F/N)".

 

"Please, what, Papyrus?  You've gotta tell me what you want so I can give it to you.  Good boys use their words and ask nicely..." You're grinding on him heatedly, your dick twitching your pleasure against the spasaming wetness.

 

He looks at you through an eye socket, orange burning deep in the holes.  You smile patiently, though your body screams for the tight chasm of his slit.  "PLEASE... PLEASE TAK-E ME, (F/N-N).  I WANT T-TO BE YOURS".

 

You grin at his words, and your cock agrees, twitching.  You pull away, taking his hand to your chest, letting him feel the rapid beating of your heart, as you pull your underwear down slowly.  He marvels at the beating in your chest and presses further on your chest, distracted a moment, before looking to your hardened cock.  He looks away, blushing softly.  "You can look," you murmur, taking his hand slowly down your chest to your hard shaft.  You encourage him to stroke.  "You can touch.  I'm yours just as much as you are mine".

 

He strokes gently, hard bones delightfully tight.  You sigh, tilting your head back, rutting into his hand, bulge slipping against his slit.  He shudders, abandoning your shaft in prospect of being filled.  You rub against his slit, teasing slightly, before giving in and thrusting your head in gently.

 

 _Fuck,_  you think.   _He's still so tight._   He howls slightly, bouncing on your dick, the knot on his strange shaft getting larger.  You get the idea, making a tight chute with your hand and round it around his cock, making Papyrus thrust up into the hand, knot catching on your fingers.  You squeeze the thick knot in your hands, slamming your cock into the ribbed passage of the slit.  He flutters around you like butterfly wings, his fingers pressing into your shoulders, scratching your back, sure to leave marks.  You moan into him, thrusting shallowly, the ribs in him quivering around you, coaxing completion.  "God, Pap.  You feel so good around me.  You're so soft, baby, love- ah!  The way you squeeze down on me.  Going to make me come so quick".

 

He whines to your words, egged on, he meets your now rapid thrusts, fucking inward onto him.  "Look so pretty, Pap, wanna love you all night long".  You hitch a leg over your shoulder making him cry your name, bending him to position yourself.  You thrust in deeper than before and he clenches rapidly on you.

 

"(F/N, I-I'M GOING TO-O-"

 

"Yeah, r-right behind ya babe".

 

You are both careening into climax before you can even say anything.  You bring yourself forward, to lick his collarbone, moaning your release, as you both blur with your release.  You pound brashly into him, easing you both down.  You pant, easing out of him.  "I wasn't too rough?" you ask worriedly.  You had lost yourself a bit near the end, rubbing yourself on his soaking slit, as it flutters against you.

 

He blushes orange.  "AH, NO... YOU WERE... YOU WERE VERY WONDERFUL.  THANK YOU VERY MUCH.  I... I NEED TO COME A FEW MORE TIMES THOUGH, IT SEEMS..." he says hesitantly pressing onto you. 

 

You grin a pull away.  "Nuh uh.  This time, I'm going to ride  _you"._ You gather the mixed come in a hand turning your back to him, shuffling to his ribs.  You turn and see him stuttering, eye sockets wide.  You spread the slick onto your hole, some dripping onto his ribs.  You take his hand in yours, coercing his now slick fingers into your hole.  You hum, flexing around him, and he moans in wonder.  You grit through the initial pain, and direct him to scissor the fingers in you.  "Gotta stretch me, baby boy.  Gonna tear me if we don't, with your nice, fat shaft," you moan, riding his fingers, as he wails beneath you, grabbing your hips in a hand, he sweeps you to his mouth, and something slippery rubs your hole.  There must be something in his slick, because you never went soft, hardness still burning despite your climax.

 

Jumping, you turn to see that he's got an orange tongue licking between your cheeks at your pucker.  It plunges in with his fingers, and you fall forwards, gasping and grinding against his tongue and fingers.  Your nose hits the bumpy cock in front of you, and you take it into your mouth desperately.  The head is soft on your pallet, and you lick the tip, making him moan against your ass, tongue plunging further into you, farther than any human tongue could ever go.  He's so deep in you, you desperately take him deeper in your throat, bumps stroking your throat in a surprisingly comforting way.  You pull off of him and his tongue scooting tword his cock.  "Sorry, darling, but I gotta ride you, or I'm going to burst before the fun begins," you gasp, looking back at him, a he pushes his hands against your hips, thumb stroking your lower back.

 

You hover over his shaft, easing the head into you.  You circle him in you softly, as you moan, before he presses into you.  You cry out in a pained pleasure.  He stutters against you.  "A-ARE YOU OKAY, (F/N)?"

 

You nod, easing him around in you, hand on your shaft.  Those small bumps are working you well, stroking you in nerves you didn't know you had, rubbing against your prostate.  "Oh babe, Pap, you're so thick.  If I knew you were so big I would'a pinned you down and rode you earlier.  Want you to fill me so bad, want you to knot me up and make me full of your come I love you so much baby doll," you string together, his shaft pounding into you, pressing your prostate making you shake and cry out repeatedly.

 

At your confession, he pulls you back against his chest as he sits up, hooking your arm around him so he can kiss you.  "I LOVE YOU TOO, (F/N)".  He rapidly hammers into you, and you can't keep up with his thrusts, despite your efforts, letting him thrust into you.  You feel his knot press against your hole and you have to fight to bear down to take it, because damn you to hell if you aren't going to take him all.  He slips halfway and he nips your ear, falling to your neck, biting softly, his sharp teeth scraping your sensitive neck.

 

You tilt your head away, loving the attention, bearing down one last time before the knot pops into you, and he thrusts harder, albeit more shallowly into you.  "Yeah, darlin', bite me, make me yours, want everyone to know I got you, my lovely, gorgeous boy.  Knot me, come in me, want you, love you, Papyrus," you scream your release, and his knot swells into you larger than ever, and his come pulses into you with his climax.  He cries his love for you into your shoulder, biting down hard enough for blood, bruising your neck and shoulder.  He reaches around to jerk you, and it only takes two before you're spilling into his hands.

 

Your sobbing, riding him softly, loving his thick knot filling you.  He comes from his dick about as much as he did from his slit, so with his knot blocking the only exit, he fills you up, your abdomen distending slightly, and you feel yourself fill.  You groan, gazing down blearily, seeing your rounding stomach.  You shakily lean back to rest on his ribs, watching his hands leave your hips to your abdomen, massaging the swollen belly.  You moan, your head throwing back to his neck's hollow, and he kisses your head.  "YOU DID SO WELL, (F/N).  I HATE TO ASK, BUT IT SEEMS I NEED TO RELEASE ONCE MORE AFTER THIS... I CAN FEEL IT," he says hesitantly.  "YOU ARE SO SOFT AND STRETCHY.  IT'S VERY APPEALING HOW FULL YOU ARE.  SHOULD I LET YOU EMPTY BEFORE FILLING YOU AGAIN?"  It doesn't sound lewd, the way he anxiously questions, but your dick doesn't seem to know that as it twitches in interest.

 

You moan.  You're so tired, but you want another load in you so badly.  You need it now that your cock has begun hardening anyway.  "No, babe.  Leave it in.  Wanna be full of you.  Wanna walk around and let everyone see that you knotted me up like a bitch.  Wanna be on your knot, you were so good baby doll".

 

He moans, spurting again in you with another string of come, you moaning as you are filled some more.  You are turned around to have your ass in the air, as he pulls out with a thick  _schlock_  and a moan from both of you, his knot pulling against your rim as you release it.  His finger dips into your loose hole, pulling some come from it.  You wail to him, "Wait, I want a taste," and he complies, watching intently as you lick his phalanges, sucking them in and tonguing, moaning at the taste of you and him mingling.  He pulls away moaning, before pulling his hips to yours, hesitantly pushing inside.  "Come on, Papyrus,  _fuck_  me," You whine, wiggling your hips, eager for his length, the ridges in his head making you moan with every dip and pull.  "I won't break baby, don't be afraid to hurt me," you say, looking back at him.

 

He looks doubtful, but presses on with a quick thrust into you, making the cum in you splurge and spill a slight bit over your packed rim.  Encouraged by your moan, he thrusts harder into you, his beaded cock stroking your walls, and you clench down, eager for more of the wonderful sensation.  On a particular thrust he crashes into your prostate and bites your neck a second time, making you yelp into the pillow you were biting against, and you slapped your hips to his, squeezing on his cock eagerly.  His response meets your quickly with a moan of praise, and his hands clench your hips, heaving you up, as he moves even closer, pressing your breast into the mattress, but your hips above you, giving him a more downward and deep thrust.

 

You howl, feeling his knot slide into you, thickening rapidly, and you climax around him.  He moans, continuing to thrust harder into your ass, before bursting himself, letting his knot fill your rim, forcing more cum into you.  He sets you down, but keeps his hips to yours as he slightly thrusts.  He comes so much longer than last time, pressing onto your back with his ribs, thrusting softly and whimpering into your ear, nibbling gently, occasionally licking the bite wounds on your neck and shoulder.  You feel along your stomach and moan at how full you feel, loving the way it presses into you.  

 

Your skeleton boyfriend goes to pull out of you, but you wail in protest making him stop in surprise.  "WHAT IS IT, (F/N)?  DID I HURT YOU?  AM I TOO MARVELOUS AND STRONG FOR YOUR FRAGILE HUMAN BODY?!"

 

You giggle tiredly.  "Sorta, babe.  I wanna keep all your climax in me, babe.  You feel so good, don't want it to go to waste," you say softly, and he blushes orange and yellow.  So cute.  You were so lucky.  "You got anything I can put in there to hold it in?"

 

He blushes and pulls out of you, you pulling your hips upward to keep the release in you, as he pulls a small plug from under his bed.  "I-I USUALLY USE THIS FOR MYSELF WHEN I'M IN HEAT BECAUSE I DON'T USUALLY HAVE ANYONE WITH ME...  YOU MAY USE IT THOUGH, SINCE I LOVE YOU SO MUCH".  He presses the rim into you and you moan against it.  It pops in perfectly, filling the spot where his knot had been.

 

You moan, easing down to the bed, his hands fluttering against your hips and stomach nervously.  "Thanks, Papyrus.  You're such a sweetie, I'm so lucky to have you".

 

He puffs his chest.  "INDEED!  BUT YOU MUSTN'T FORGET THAT I AM LUCKY TO HAVE YOU, HUMAN!"  He softly kneads your swollen stomach, and you moan at the shifting of fluid, making you squirm slightly, edging you to his side.

 

You shift your stomach, cuddling to your sleepy skeleton boyfriend.  It's going to be a long night.

**Author's Note:**

> Sans knew it was going to happen, so like a good bro, he got his brother laid. All hail the best wingman.


End file.
